Tapered pole and method and apparatus for producing same

ABSTRACT

A tapered pole design and a method and apparatus for producing tapered poles are provided. The apparatus includes a tapered mandrel, means for rotating the mandrel, means for directing a tapered strip onto the mandrel, and means for placing the strip in tension as it is wound on the mandrel in a pseudo-helical manner. The tapered strip is preferably curved or formed in several segments attached together in end-to-end relationship at angles formed between the first strip segment and subsequent ones. Longitudinally extending edge portions of the tapered strip preferably slant downwardly to the plane of the strip prior to being wound on the mandrel. This counteracts a tendency for the edges of the strip to curl up when wound under tension. The pole can be removed from the tapered mandrel by a spinning technique or by employing a collapsible mandrel. The pole itself can be made from two separate tapered strips which are wound in opposite directions to provide a double wall tapered pole of maximum strength and stiffness.

United States Patent m1 Cauffiel 1 1 TAPERED POLE AND METHOD ANDAPPARATUS FOR PRODUCING SAME Ford B. Cauffiel. 4940 Homerdale Ave.Toledo. Ohio 43623 [22] Filed: Aug. 28. I973 [21] Appl. No.: 392,259

Related U.S. Application Data [62] Division of Ser. No. 212.228. Dec.27. 1971. Pat. No.

[76] Inventor:

[52] U.S. Cl. 72/137: 29/DlG. 41: 72/138: 72/183; 72/370 [51] Int. ClB2" 35/02 158] Field of Search 72/167. 168. 183. 137.

72/133. 135. 138. 370: 29/4773. DIG. 41. 155 C; 113/116 UT [451 Apr. 29,1975 Prinmr Etaminer-C'. W. Lanham Assistant Emminvr-Robert M. RogersAttorney. Agent. or FirmAllen D. Gutchess. Jr.

[57] ABSTRACT A tapered pole design and a method and apparatus forproducing tapered poles are provided. The apparatus includes a taperedmandrel. means for rotating the mandrel. means for directing a taperedstrip onto the mandrel. and means for placing the strip in tension as itis wound on the mandrel in a pseudo-helical manner. The tapered strip ispreferably curved or formed in several segments attached together inend-to-end relationship at angles formed between the first strip segmentand subsequent ones. Longitudinally extending edge portions of thetapered strip preferably slant downwardly to the plane of the stripprior to being wound on the mandrel. This counteracts a tendency for theedges of the strip to curl up when wound under tension. The pole can beremoved from the tapered mandrel by a spinning technique or by employinga collapsible mandrel. The pole itself can be made from two separatetapered strips which are wound in opposite directions to provide adouble wall tapered pole of maximum strength and stiffness.

[7 Claims. [6 Drawing Figures PMENTEDAPRZQIQYS Ilf SHEET 1!]? 3 PATENTEUE 3,879,977

PIG. 13

TAPERED POLE AND METHOD AND APPARATUS FOR PRODUCING SAME This is adivision of application U.S. Ser. No. 212.228 filed Dec. 27. l97l. nowUS. Pat. No. 3.77l.978.

This invention relates to a method and apparatus for producing taperedpoles. to a strip from which the pole can be made. and to a specifictapered pole design.

Poles of the type having larger diameters at the base and smallerdiameters at the top. as used for street lights. tall signs. etc.. areoften made from nested cylindrical tubes of varying diameters which nestwithin one another and are welded together at their junctures. Thetechniques heretofore known for making tapered poles have been slow andexpensive. using more metal than necessary for proper strength. and alsorequiring machinery which is both costly and space consuming.

The present invention provides a method and apparatus for making atapered pole from a particular tapered strip which is wound in apseudo-helical manner on a tapered mandrel. Means are provided fordirecting and guiding the strip on to the mandrel and means are providedfor establishing relative movement between the directing means and themandrel in a direction such that the strip is wound from the small endof the mandrel toward the large end. Means are also provided for placingthe strip under tension when wound on the mandrel. the tensioning meanspreferably being associated with the directing means. The longitudinaledges of the strip also can be formed downwardly from the plane of thestrip. This configuration of the strip helps to counteract the tendencyof the edges thereof to curl up when wound under tension on to themandrel.

The strip according to the invention preferably is shaped in a mannersuch that the angle between portions of the strip at the narrow end andthe axis of the mandrel is smaller than the corresponding angle betweenportions of the strip at the outer end and the axis of the mandrel, whenthe strip is in a position to be wound on the mandrel. Stated anotherway. the strip curves or extends in a direction away from the large endof the mandrel. The strips can be formed in a number of segments whichare affixed. as by welding. in end-to-end relationship. with eachsubsequent segment forming a larger included angle with the firstsegment than does the preceding segment. However. the strip also can bemade with a continuously curved shape from the narrow. first end towardthe outer end.

To remove the pole from the mandrel. a spinning technique can beemployed in which the pole is spun at a relatively high speed and withpressure rollers or the like then urged against the wall of the pole.The wall thickness is thereby reduced slightly and the diameter of thepole is correspondingly increased so that the pole is thereby easilyremoved from the mandrel. Rather than the spinning technique. thetapered mandrel can be designed to be collapsible to facilitate removalof the pole.

The invention also includes a double wall pole having an inner wallwhich is formed by a tapered strip wound in a pseudo-helical manner witha lead angle in one direction. Around this is wound a second taperedstrip wound in a pseudo-helical manner with a lead angle extending inthe opposite direction. This type of pole has ultimate strength andstiffness not otherwise possible to obtain except with extremely heavypoles.

It is. therefore. a principal object of the invention to provide amethod and apparatus for making a tapered pole on a tapered mandrel froma tapered strip with the strip placed under tension as it is wound onthe mandrel.

Another object of the invention is to provide a tapered strip forforming a tapered pole. which strip is made from a plurality of segmentsattached in end-toend relationship. with each subsequent segment beingat a larger angle to the first segment than is the preceding segment.

Still another object of the invention is to provide a tapered strip forforming a tapered pole. which strip is shaped in a manner to decreasethe lead angle of the pseudo-helical position ofthe strip when woundinto a tapered pole form.

Yet another object of the invention is to provide a method and apparatusfor producing a tapered pole on a tapered mandrel and removing the polefrom the mandrel by reducing the wall thickness of the pole to expandits diameter.

Yet a further object of the invention is to provide apparatus forproducing a tapered pole embodying a collapsible tapered mandrel.

Still a further object of the invention is to provide a tapered polehaving a double wall. each all being formed from a tapered strip woundin a pseudo-helical manner. with the strips wound in oppositedirections.

Many other objects and advantages of the invention will be apparent fromthe following detailed description of preferred embodiments thereof.reference being made to the accompanying drawings. in which:

FIG. I is a somewhat schematic side view in elevation of overallapparatus for producing a tapered pole on a tapered mandrel;

FIG. 2 is a somewhat schematic top view of the overall apparatus of FIG.1'.

FIG. 3 is a view in transverse cross section taken along the line 3-3 ofFIG. I;

FIG. 4 is an enlarged. fragmentary view in transverse cross sectiontaken along the line 4-4 of FIG. 2:

FIG. 5 is a view in transverse cross section through a tapered strip.taken along the line 55 of FIG. 2'.

FIG. 6 is an enlarged. fragmentary cross-sectional view taken throughtwo wraps of a tapered strip with a narrow. thinner strip located belowthe adjacent edges of the tapered strip;

FIG. 7 is a fragmentary view. with parts broken away. of a tapered polehaving a double wall. the inner wall constituting a tapered strip woundin a pseudo-helical manner in one direction and the outer wallconstituting a tapered strip wound in a pseudo-helical manner in theopposite direction;

FIG. 8 is a somewhat schematic plan view of a tapered mandrel and asegmented tapered strip according to the invention;

FIG. 9 is a fragmentary view of a portion of a tapered pole formed byattached segments of the strip of FIG.

FIG. 10 is a view similar to FIG. 8 of a modified tapered strip;

FIG. 11 is a schematic plan view of apparatus for facilitating removalof a wound tapered pole from a ta pered mandrel;

FIG. I2 is an enlarged. schematic view in cross section taken generallyalong the line 12-12 of FIG. ll

FIG. 13 is a schematic. fragmentary view in longitudi nal cross sectionof a tapered collapsible mandrel em bodying the invention;

FIG. I4 is a view in transverse cross section taken along the line I4-I4of FIG. I3;

FIG. I5 is a view similar to FIG. I3 of a modified col- Iapsihlemandrel; and

FIG. I6 is a view in transverse cross section taken along the line l6l6of FIG. I5.

Referring to the drawings, and particularly to FIGS. I and 2. overallapparatus for supporting and rotating a tapered mandrel is indicated at20. The apparatus can be in the form of a large lathe. including a bed22, a headstock 24. and a tailstock 26. The headstock 24 has a spindle27 rotated by a suitable motor 28. with the spindle having jaws 30. Thetailstock 26 has an ad' justable spindle 32 and is longitudinallymovable on ways 34 and 36. A tapered mandrel 38 is engaged by the jawsof the spindle 26 with the opposite end held by the spindle 32. Thelatter is positioned so that the front surface of the mandrel 38, andspecifically a line on the front surface which is tangential to avertical plane. is parallel to the frontway 34. Various other apparatuscan be used to support and rotate the mandrel. including the apparatusshown in my copending application. Ser. No. l77.992.

By way of illustration, in a particular example. the mandrel 38 is V1feet long with a 3 inch diameter at the small end and a 9 inch diameterat the large end, representing a slope of I). I42 inches per foot oflength. However. most commercial tapered poles will require a longermandrel.

A tapered strip 40 is wound on the mandrel 38. being quided thereon by adirecting means or carriage 42. As shown more particularly in FIG. 3,the carriage 42 is slidably mounted on the ways 34 and 36. A threadedrod 44 extends the length of the bed 22 and passes through the carriage42. engaging a gear (not shown) carried by the carriage 42. The gear isdriven through sprockets 46. 48. and a chain by a suitable motor 52mounted on the carriage. In this manner. the carriage 42 is driven alongthe ways 34 and 36 and accordingly directs the tapered strip 40.

The carriage 42 has an upstanding frame 54 on which is mountedtensioning means indicated at 56. Referring particularly to FIG. 4. thetensioning means include a structural platform 58 affixed to the top ofthe frame 54. on which platform are two lower blocks 60. A wear plate 62is located on top of the blocks with the strip 40 riding on the plate62. Two additional blocks 64 are in direct contact with the top surfaceof the strip 40, in this instance. Structural channels 66 are located ontop of the blocks 64 and receive bolts 68 which extend completelythrough the platform 58, the blocks 60 and 64. the wear plate 62, andthe structural back-up channels 66 where they receive nuts 70. Thedegree to which the nuts are tightened on the bolts 68 regulates theamount of drag or friction of the blocks 60 and 64 and the plate 62 onthe tapered strip 40, and. hence, the amount of tension on the strip.The upper channels 66 help assure uniformity of the tension on the strip40 across the width thereof regardless of the location of the strip 40in the tensioning means 56. In practice, it has been found to be veryimportant to place tension on the strip 40 as it is being wound on themandrel 38 in order to smoothly and uniformly wrap the strip on themandrel.

The carriage 42 guides and directs the strip 40 on the mandrel 38,according to the longitudinal position of the carriage, while thetensioning means 56 provide the tension on the strip. and yet enablesthe angle of the strip to change as it is wound on the mandrel.

Arms 72 extend from the frame 54 and have contact shoes 74 which engagethe mandrel 38 or the newly wound strip 40 on the mandrel. This providessupport between the mandrel and the tensioning means 56 to prevent thetension means from being pulled toward the mandrel as tension is appliedto the strip 40.

A pair of contact shoes 76 mounted on a yoke 78 are also located on theopposite side of the mandrel 38 and are urged thcreagainst by a fluidoperated ram 80. These shoes help support the axis of the mandrel in afixed position the mandrel rotates, despite the side forces appliedthereto as the strip is wound thereon. The ram 80 is affixed to asupport 82 which is also part of the carriage 42.

The wear strip 62 is employed on the blocks 60 because edge portions 84(FIG. 5) of the strip 40 slant downwardly slightly, preferably at anangle of from 1 to 8. This angular disposition of the strip edgesovercomes the tendcncy of the strip edges to curl upwardly .when woundon the mandrel 38 under tension. If the strip is of soft metal orplastic. by way of example, the wear plate 64 is not necessary even ifthe edge portions of the strip do slant downwardly.

When the strip is wound on the mandrel. adjacent wraps 86 and 88, shownin FIG. 6, are joined by a continuous pseudo-helical bead of weld metal90. To avoid the possibility of welding the wraps to the mandrel 38 andto avoid possible damage to the mandrel. a narrow. thin strip 92 can bewound around the mandrel along with the strip 40 and positioned tobridge and underlie the contiguous edges of the adjacent wraps 86 and88.

In instances where a strong, stiff pole is desired, a double-wall pole94 of FIG. 7 can be made. Accordingly. an inner wall 96 of the pole canbe formed by a tapered strip 98 with the edges welded as in FIG. 6. withor without the strip 92. An outer wall 100 is then formed over the innerwall 96 by winding a strip I02 thereon. The lead angle of the innerstrip 98 is opposite to the lead angle of the strip I02 so that a strongand stiff pole is achieved. This pole can be made by winding the strip98 from the side of the mandrel opposite to that shown in FIG. 2. Whenthe strip is wound and welded. the strip 102 can be wound on the innerwall 96 from the side shown in FIG. 2. In the first instance, themandrel is rotated in a clockwise direction. as viewed from the largeend thereof. In the second instance, the mandrel is rotated in acounter-clockwise direction.

The strip 40 is not wound on the mandrel 38 in a truly helical mannerbut. rather, in a pseudo-helical manner. For example, at the beginningthe angle of the strip may be 60 to the axis of the mandrel 38 with thelongitudinal edges of the strip forming an included angle of 2 and withthe strip being I inch wide. By the time a 20 foot length of the mandrelhas been wound, the angle of the strip to the axis of the mandrel mayhave decreased to 1S-30". At this time, the angle has become so narrowas to make proper winding while still retaining tension on the stripextremely difficult. Consequently, it may be desirable to change theangle of the strip as winding progresses, particularly for longer poles.

Poles of lengths to meet most commercial purposes are sufficiently longthat the angle of the tapered strip 40 becomes unduly narrow before thefull pole can be wound. To overcome this problem. the strip 40 issegmented (FIG. 8). with three segments I04. I06. and I08 being shown.with the segments being equal in size and shape in this instance. Theseare joined in end-toend relationship by suitable means and preferably bywelds IIO and 112. The three strip segments I04. I06 and 108 extend in adirection away from the large end of the mandrel 38. Further. each ofthe segments forms a larger included angle with the first segment thandoes the immediately preceding segment. Thus. the third segment 108forms a larger angle with the first segment 104 than does the secondsegment I06. While each of the segments I04. I06. and I08 is shaped witha long taper away from the mandrel 38, the wider end of each is alsoshaped with a short taper in the opposite direction. The short tapersare shown at a portion I14 for the segment I04. and 116 for the segmentI06. for example. The larger end portions of the segments thereby aretapered down to the same width as the narrow ends of the next.subsequent strip segments. For the edges of the adjacent wraps of thesegments I04 and I06. for example. to meet smoothly and contiguously.the tapered portion I I4 of the segment 104 forms a straightcontinuation of the outer or longer edge of the segment 106 and the sameis true for the tapered portion I16 and any subsequent tapered portions.The length of the straight continuation preferably equals thecircumference of the mandrel at the location when that portion of thestrip is to be wound. This enables that edge to be contiguous with theopposite edge of the subsequent segment.

The strip also can be formed in a continuous curve as indicated at 117in FIG. I0. rather than the segmented one. as shown in FIG. 8.

Particularly when the tapered pole is to be made of deformable orductile materials. such as aluminum. the wound pole on the mandrel canbe subjected to a spin ning technique by means of which the wallthickness of the pole is reduced slightly and the diameter is increased.whereby the pole can then be easily removed from the mandrel. Apparatusfor this purpose is schematically shown in FIGS. II and I2. In thisinstance, after a tapered pole H8 is wound. it can be turned at a higherrate of speed and subjected to pressure by rollers I20, I22, and I24.The roller I20 is mounted on a frame 126 while the rollers I22 and 124are mounted on a yoke 128 which is urged toward the pole II8 by afluid-operated ram 130. The latter is mounted on a support I32 which ismounted on a carriage I34 along with the frame I26, with the assemblythen being moved along the pole by suitable means. the carriage beingslidably supported on the ways 34 and 36. The forward surface of thepole I18 again is parallel to the from way 34 so that the stationaryroller I20 remains in a fixed relationship to the pole. The pressureexerted by the rollers on the pole reduces the thickness of a wall I36of the pole 118, thereby causing the diameter of the pole to increaseand enable it to be easily removed from the mandrel 38.

The tapered pole can also be more readily removed from the mandrel if acollapsible mandrel is employed. Various types of such mandrels can beused. two representative ones being schematically shown in FIGS. 13, 14,and I5, 16.

Referring to FIGS. 13 and 14, a collapsible mandrel 138 includes twomain sections 140 and 142 having outer arcuate configurations and havinginner wedges I44 and I46 extending toward one another. An intermediatesection I48 has arcuate end portions forming a cylindrical cross sectionin cooperation with the sections I and 142. The section I48 further hasupper and lower recesses I50 and I52 terminating in slanted ends I54 andI56. With the sections 140. I42 and I48 being in the longitudinalrelative positions shown in FIG. I3. the mandrel 138 is collapsed. asshown in FIG. 14. so that the pole wound thereon can be removed from thesmall end. When the central section 148 is moved longitudinally towardthe right. as viewed in FIG. 13. the outer sections I40 and I42 will beexpanded to form a circular cross section with the central section. Insuch position. the pole can be wound thereon.

Another collapsible mandrel I58 is shown in FIGS. I5 and 16. where. acentral core section 160 extends the full length of the mandrel and hasspaced lower recesses I62 in which ears 164 and 166 of substantiallysemi-cylindrical mandrel sections 168 and I70 are pivotally connected bypins I72. The upper edge of the core I has a central channel or groove174 in which is slidahly supported a longitudinally-extending edge I76.The wedge I76 moves the sections I68 and I in and out as the wedge I76is forced longitudinally in the channel I74. In the position shown inFIG. I6. the sections I68 and 170 are in outer positions to form acircular cross section for the mandrel 158. After a pole is woundthereon, the wedge I76 is moved toward the left as viewed in FIG. I5. toenable the sections 168 and 170 to move inwardly.

Various modifications of the above described embodiments of theinvention will be apparent to those skilled in the art. and it is to beunderstood that such modifications can be made without departing fromthe scope of the invention if they are within the spirit and the tenorof the accompanying claims.

I claim:

I. Apparatus for producing a tapered pole comprising an elongate.tapered mandrel. means for rotating said mandrel. an elongate strip.means for directing the elongate strip onto said mandrel in apseudo-helical manner as the mandrel rotates. with edges of the striplying in contiguous relationship. means for applying pressure to bothsides of said strip for placing under tension the portion of the stripbetween said directing means and said mandrel. with the tension beingsubstantially constant over the width of the strip.

2. Apparatus according to claim 1 characterized by means for moving saiddirecting means along a line parallel to the closest surface of saidmandrel.

3. Apparatus according to claim 1 characterized further by said stripcomprising a plurality of tapered strip segments connected together inend to-end relationship.

4. Apparatus according to claim 3 characterized by each subsequent stripsegment being located at an angle to the previous strip segment to whichit is connected.

5. Apparatus according to claim 3 characterized further by there beingat least three strip segments. each subsequent strip segment lying at agreater angle to the first strip segment than does the preceeding stripsegment.

6. Apparatus according to claim 1 characterized by said elongate stripcurving substantially continuously from one end to the other in theplane of the strip.

7. Apparatus according to claim I characterized further by bothlongitudinal edge portions of said elongate strip slanting downwardlyfrom the plane of the strip prior to the strip being wound on themandrel.

8. Apparatus according to claim I characterized by said tension meansbeing located near said mandrel. said tension means having contact meansextending toward and into contact with said mandrel as the strip isbeing wound thereon.

9. Apparatus according to claim 8 characterized further by supportingcontact means located generally on the other side of the mandrel fromsaid contact means. and means for urging said supporting contact meansto ward said mandrel.

10. Apparatus according to claim 1 characterized further by said taperedmandrel being collapsible.

1]. Apparatus according to claim 1 characterized further by pressuremeans for applying force to the wound elongate strip on the mandrel toreduce the thickness of the strip and increase the diameter of the poleon the mandrel.

l2. A method for producing a tapered pole comprising supporting anelongate. tapered mandrel for rotation about its axis. rotating saidmandrel. directing an elongate strip in a pseudohelical manner onto themandrel as the mandrel rotates. with edges of the strip lying incontiguous relationship. and engaging both sides of the strip forplacing the strip under tension as it is wound onto the mandrel.

IS. A method according to claim 12 characterized by placing the stripunder tension by leading the strip between a pair ofmcmbers while urgingsaid members toward one another.

14. A method according to claim 12 characterized further by abruptlychanging the angle between the strip and the axis of the mandrel atleast once as the strip is wound onto the mandrel.

[5. A method according to claim 12 characterized by maintaining theangle between the axis of the mandrel and that portion of the stripbeing wound on the mandrel substantially constant as the strip is woundonto the mandrel.

16. A method according to claim 12 characterized by reducing thethickness of the strip after the strip is wound on the mandrel toincrease the diameter of the pole on the mandrel.

17. A method according to claim 12 characterized by reducing the size ofsaid mandrel after the strip is wound thereon to facilitate removal ofthe pole from said mandrel.

1. Apparatus for producing a tapered pole comprising an elongate, tapered mandrel, means for rotating said mandrel, an elongate strip, means for directing the elongate strip onto said mandrel in a pseudo-helical manner as the mandrel rotates, with edges of the strip lying in contiguous relationship, means for applying pressure to both sides of said strip for placing under tension the portion of the strip between said directing means and said mandrel, with the tension being substantially constant over the width of the strip.
 2. Apparatus according to claim 1 characterized by means for moving said directing means along a line parallel to the closest surface of said mandrel.
 3. Apparatus according to claim 1 characterized further by said strip comprising a plurality of tapered strip segments connected together in end-to-end relationship.
 4. Apparatus according to claim 3 characterized by each subsequent strip segment being located at an angle to the previous strip segment to which it is connected.
 5. Apparatus according to claim 3 characterized further by there being at least three strip segments, each subsequent strip segment lying at a greater angle to the first strip segment than does the preceeding strip segment.
 6. Apparatus according to claim 1 characterized by said elongate strip curving substantially continuously from one end to the other in the plane of the strip.
 7. Apparatus according to claim 1 characterized further by both longitudinal edge portions of said elongate strip slanting downwardly from the plane of the strip prior to the strip being wound on the mandrel.
 8. Apparatus according to claim 1 characterized by said tension means being located near said mandrel, said tension means having contact means extending toward and into contact with said mandrel as the strip is being wound thereon.
 9. Apparatus according to claim 8 characterized further by supporting contact means located generally on the other side of the mandrel from said contact means, and means for urging said supporting contact means toward said mandrel.
 10. Apparatus according to claim 1 characterized further by said tapered mandrel being collapsible.
 11. Apparatus according to claim 1 characterized further by pressure means for applying force to the wound elongate strip on the mandrel to reduce the thickness of the strip and increase the diameter of the pole on the mandrel.
 12. A method for producing a tapered pole comprising supporting an elongate, tapered mandrel for rotation about its axis, rotating said mandrel, directing an elongate strip in a pseudo-helical manner onto the mandrel as the mandrel rotates, with edges of the strip lying in contiguous relationship, and engaging both sides of the strip for placing the strip under tension as it is wound onto the mandrel.
 13. A method according to claim 12 characterized by placing the strip under tension by leading the strip between a pair of members while urging said members toward one another.
 14. A method according to claim 12 characterized further by abruptly changing the angle between the strip and the axis of the mandrel at least once as the strip is wound onto the mandrel.
 15. A method according to claim 12 characterized by maintaining the angle between the axis of the mandrel and that portion of the strip being wound on the mandrel substantially constant as the strip is wound onto the mandrel.
 16. A method according to claim 12 characterized by reducing the thickness of the strip after the strip is wound on the mandrel to increase the diameter of the pole on the mandrel.
 17. A method according to claim 12 characterized by reducing the size of said mandrel after the strip is wound thereon to facilitate removal of the pole from said mandrel. 